Centrifugal blower and air conditioner having the same

ABSTRACT

A centrifugal blower capable of preventing generation of a swirled air stream in a space between the inner surface of a casing and a side end of a centrifugal fan, and an air conditioner having the same. The centrifugal blower includes a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet, a centrifugal fan installed in the casing, and a stream-cutoff member provided at an inner surface of the casing around the bell-mouth to prevent an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2007-0027769, filed on Mar. 21, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

One or more embodiments of the present invention relate to a centrifugal blower and an air conditioner having the same, and, more particularly, to a centrifugal blower which may prevent generation of a swirled air stream in a space between the inner surface of a casing and a side end of a centrifugal fan, and an air conditioner having the same.

2. Description of the Related Art

A centrifugal blower is used in an air conditioner, etc. to blow air. One example of an air conditioner having a centrifugal blower is disclosed in Korean Patent Laid-Open Publication No. 2006-0090839.

The conventional centrifugal blower, disclosed in the above Publication, includes a casing to guide a current of air, and a centrifugal fan installed in the casing. The casing has air inlets formed in both side surfaces of the casing to suction air, and air outlets formed in a direction crossing the air inlets to blow the suctioned air. The casing also has curved bell-mouths provided at the air inlets.

The centrifugal fan installed in the casing includes a rotating plate coupled to a rotating shaft, a plurality of blades annularly arranged about the rotating shaft at opposite outer-peripheral surfaces of the rotating plate, each blade having a first end fixed to the rotating plate, and supporting rings to support the outer periphery of the second ends of the blades.

Referring to FIG. 1 showing the above described centrifugal fan included in the conventional centrifugal blower, since the supporting rings 1 a connect the outer periphery of the second ends of the respective blades 1 b to each other, the second ends of the blades 1 a located close to the bell-mouths 3 of the casing 2 are opened. When the supporting rings 1 a are used to connect the outer periphery of the second ends of the blades 1 b to each other in order to reinforce the strength of the blades 1 b, substantially, the centrifugal fan 1 has no shroud to guide a current of air.

If the centrifugal fan 1 rotates within the casing 2, air is suctioned toward the center of the centrifugal fan 1 through the air inlets 4, and thereafter, is blown toward the periphery of the centrifugal fan 1 within the casing 2.

However, since the second ends of the respective blades 1 b of the centrifugal fan 1 located close to the bell-mouths 3 of the casing 2 are opened (i.e. have no air-guiding shroud) and also, the second ends of the blades 1 b are spaced apart from the inner surface of the casing 2 at the outside of the bell-mouths 3, there is a problem in that air is swirled in spaces 5 between the second ends of the respective blades 1 b and the inner surface of the casing 2. Specifically, as represented by the arrow A of FIG. 1, the air in the vicinity of the second ends of the blades 1 a flows backward along the inner surface of the casing 2, and is again suctioned inward of the blades 1 a, causing a swirled air stream.

The swirled air stream A disturbs a main air stream B, resulting in poor blowing efficiency and severe air flow noise. In particular, in the case of the centrifugal blower employing a turbo fan having no shroud at the second ends of the blades 1 a, the above described problem may be made worse.

SUMMARY

Accordingly, one or more embodiments of the present invention provide a centrifugal blower which may prevent generation of a swirled air stream in a space between the inner surface of a casing and a side end of a centrifugal fan, and an air conditioner having the same.

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

To achieve at least the above and/or other aspects and advantages, embodiments of the present invention include a centrifugal blower including, a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet, a centrifugal fan installed in the casing, and a ring-shaped stream-cutoff member provided at an inner surface of the casing around the bell-mouth to prevent an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.

In an embodiment, the stream-cutoff member may have a ring shape protruding from the inner surface of the casing to be close to the side end of the centrifugal fan, and an outer diameter of the stream-cutoff member may be smaller than an outer diameter of the centrifugal fan.

In an embodiment, the centrifugal fan may be a turbo fan having an opened side end close to the stream-cutoff member.

In an embodiment, the stream-cutoff member may include a stream guiding plane close to the side end of the centrifugal fan, the stream guiding plane having the same width as a radial blade length of the centrifugal fan.

To achieve at least the above and/or other aspects and advantages, embodiments of the present invention include an air conditioner having a body, a heat exchanger installed in the body, and a centrifugal blower installed in the body to blow air, the centrifugal blower including, a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet, a centrifugal fan installed in the casing, and a stream-cutoff member provided at an inner surface of the casing near the bell-mouth to prevent an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.

To achieve at least the above and/or other aspects and advantages, embodiments of the present invention include a centrifugal blower including, a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet, a centrifugal fan installed in the casing, and means for preventing an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.

To achieve at least the above and/or other aspects and advantages, embodiments of the present invention include a method of preventing an air stream from being swirled in a space between an inner surface of a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet, and a side end of a centrifugal fan installed in the casing. The method includes providing a ring-shaped stream-cutoff member at an inner surface of the casing around the bell-mouth.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a sectional view of a conventional centrifugal blower;

FIG. 2 is a sectional view showing an air conditioner having a centrifugal blower, according to an embodiment of the present invention;

FIG. 3 is a perspective view showing a stream-cutoff member included in the centrifugal fan, according to an embodiment of the present invention;

FIG. 4 is a sectional view of the stream-cutoff member shown in FIG. 3; and

FIG. 5 is a sectional view showing another embodiment of the stream-cutoff member included in the centrifugal fan according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

FIG. 2 is a sectional view showing an air conditioner having a centrifugal blower according to an embodiment of the present invention. The air conditioner may include, for example, a body 10, a heat exchanger 11 installed in the upper region of the body 10, and a centrifugal blower 30 installed in the lower region of the body 10.

The body 10 may have, for example, suction holes 12 formed in a rear wall or both sidewalls thereof at lower positions to suction indoor air, lateral-side discharge holes 13 formed in both the sidewalls thereof at upper positions, and a front-side discharge hole 14 formed in the center of a front wall thereof. An upper door 15 may be installed in the upper portion of the front wall of the body 10 to open or close the front-side discharge hole 14. The upper door 15 may be movable vertically along rails (not shown) installed at the body 10. To move the upper door 15 vertically, a lifting device 16 may be installed at a rear surface of the upper door 15.

The heat exchanger 11 provided in the body 10 may have a flat-plate shape to allow air blown upward from the centrifugal blower 30 to be heat exchanged while passing through the heat exchanger 1. The heat exchanger 11 may be obliquely installed to divide the inner upper space of the body 10.

The centrifugal blower 30 may include, for example, a casing 31, a centrifugal fan 40 installed in the casing 31, and a drive motor 50 to drive the centrifugal fan 40. The drive motor 50 may be fixed to an inner surface of the rear wall of the body 10, and the centrifugal fan 40 may be coupled to a rotating shaft 51 extending from the drive motor 50 to the center of the casing 31.

A first air inlet 32 and a second air inlet 33 may be formed in front and rear walls of the casing 31, respectively, to suction air toward the rotating shaft 51. Also, an air outlet 34 may be formed in an upper wall of the casing 31 to discharge the suctioned air. That is, the air may be suctioned into the casing 31 through the two air inlets 32 and 33 and discharged through the upper air outlet 34. The first and second air inlets 32 and 33 of the casing 31 may be provided, respectively, with first and second bell-mouths 35 and 36. The first and second bell-mouths 35 and 36 may be curved inward of the casing 31 to guide the air being suctioned into the casing 31.

The centrifugal fan 40 is able to suction air through the first and second air inlets 32 and 33 formed in the front and rear walls of the casing 31. That is, the centrifugal fan 40 may suction air from opposite directions. The centrifugal fan 40, as shown in FIGS. 2 and 3, may include, for example, a rotating plate 41 coupled to the rotating shaft 51, a plurality of first blades 42 fixed to a front outer-peripheral surface of the rotating plate 41, and a plurality of second blades 43 fixed to a rear outer-peripheral surface of the rotating plate 41. The first and second blades 42 and 43 may be annularly arranged about the rotating shaft 51. First ends of the respective first blades 42 toward the first bell-mouth 35 may have an opened shape (having no shroud), and first ends of the respective second blades 43 toward the second bell mouth 36 may be connected to each other by a shroud 44. The centrifugal fan 40 may be a turbo fan or multi-blade sirocco fan having radial long-length blades, for example.

If the centrifugal fan 40 rotates by operation of the drive motor 50, as shown in FIG. 2, the centrifugal blower 30 may suction air through the first and second air inlets 32 and 33, to blow the suctioned air to the upper air outlet 34. Here, the air is first guided to the center of the centrifugal fan 40 by the first and second bell-mouths 35 and 36, and thereafter, may be blown in a radial outward direction through a space between the first blades 42 and the second blades 43.

The centrifugal blower 30, as shown in FIGS. 2 to 4, further may include one or more stream-cutoff members 60, provided for example, at the inner surface of the casing 30 around the first and second bell-mouths 35 and 36, respectively, to block spaces 38 between the inner surface of the casing 31 and opposite side ends of the centrifugal fan 40. Each stream-cutoff member 60 may have a ring shape protruding from the inner surface of the casing 31 to be close to the associated side end of the centrifugal fan 40. An outer diameter of the stream-cutoff member 60 may be smaller than that of the centrifugal fan 40.

As described above and as shown in FIG. 4, the stream-cutoff members 60 block the spaces 38 between the inner surface of the casing 31 around the first and second bell-mouths 35 and 36 and both the ends of the centrifugal fan 40, thereby preventing the air, blown in a radial direction of the centrifugal fan 40, from being introduced into and swirled in the spaces 38 between the inner surface of the casing 31 and both the ends of the centrifugal fan 40.

The conventional centrifugal blower, as shown in FIG. 1, may cause the swirled air stream A in the space between the centrifugal fan and the inner surface of the casing. However, the centrifugal blower 30 of embodiments of the present invention may eliminate or minimize the problem of the swirled air stream of the conventional centrifugal blower because the stream-cutoff members 60 may prevent the introduction of air streams into the spaces 38 between the inner surface of the casing 31 and the side ends of the centrifugal fan 40. Consequently, the present invention may prevent or minimize deterioration in blowing efficiency and the generation of air flow noise due to the swirled air stream.

In an embodiment, the advantageous effects of the stream-cutoff member 60, as shown in FIG. 4, may be enhanced when it is applied to a centrifugal fan having no shroud, in the same manner as the centrifugal fan 40 using the first blades 42 each having open-sided ends. This is because the stream-cutoff member 60 may prevent the introduction of air streams into the centrifugal fan 40 through the opened side end of the first blade 42.

FIG. 5 illustrates another embodiment of the stream-cutoff member. In the embodiment shown in FIG. 5, the spaces between the side ends of the centrifugal fan 40 and the inner surface of the casing 31 (e.g., the spaces around the respective bell-mouths whose outer perimeter are defined by the inner surface of the casing, an interior surface of the bellmouth and the side end of the centrifugal fan) may be completely filled with the stream-cutoff members 70 to prevent the generation of a swirled air stream. Each stream-cutoff member 70 may have a stream guiding plane 71 close to the opened side ends of the respective first blades 42, and the stream guiding plane 71 may have the same length as a radial length of each first blade 42. Here, the blown air may be guided in a radial outward direction of the centrifugal fan 40 along the stream guiding plane 71, achieving high blowing efficiency without the risk of a swirled air stream.

As apparent from the above description, embodiments of the present invention provide a centrifugal blower having a stream-cutoff member to block a space between the inner surface of the casing around a bell-mouth and a side end of a centrifugal fan. Providing the stream-cutoff member generally has the effect of preventing the generation of a swirled air stream between the side end of the centrifugal fan and the inner surface of the casing. As a result, the present invention may enhance the blowing efficiency of air and reduce air flow noise.

Although a few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A centrifugal blower comprising: a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet; a centrifugal fan installed in the casing; and a ring-shaped stream-cutoff member provided at an inner surface of the casing around the bell-mouth to prevent an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.
 2. The centrifugal blower according to claim 1, wherein the stream-cutoff member protrudes from the inner surface of the casing to be close to the side end of the centrifugal fan, and an outer diameter of the stream-cutoff member is smaller than an outer diameter of the centrifugal fan.
 3. The centrifugal blower according to claim 2, wherein the centrifugal fan is a turbo fan having an opened side end close to the stream-cutoff member.
 4. The centrifugal blower according to claim 2, wherein the stream-cutoff member includes a stream guiding plane close to the side end of the centrifugal fan, the stream guiding plane having the same width as a radial blade length of the centrifugal fan.
 5. The centrifugal blower according to claim 1, wherein the ring-shaped stream-cutoff member has a diameter and a width, and the width protrudes from the inner surface of the casing in a substantially orthogonal direction and extends close to, without touching, the side end of the centrifugal fan.
 6. The centrifugal blower according to claim 1, wherein the ring-shaped stream-cutoff member is mounted on the inner surface of the casing and substantially fills a space defined by the inner surface of the casing, and an interior surface of the bellmouth and the side end of the centrifugal fan.
 7. An air conditioner having a body, a heat exchanger installed in the body, and a centrifugal blower installed in the body to blow air, the centrifugal blower comprising: a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet; a centrifugal fan installed in the casing; and a stream-cutoff member provided at an inner surface of the casing near the bell-mouth to prevent an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan.
 8. The air conditioner according to claim 7, wherein the stream-cutoff member has a ring shape protruding from the inner surface of the casing to be close to the side end of the centrifugal fan, and an outer diameter of the stream-cutoff member is smaller than an outer diameter of the centrifugal fan.
 9. The air conditioner according to claim 8, wherein the centrifugal fan is a turbo fan having an opened side close to the stream-cutoff member.
 10. The air conditioner according to claim 8, wherein the stream-cutoff member includes a stream guiding plane close to the side end of the centrifugal fan, the stream guiding plane having the same width as a radial blade length of the centrifugal fan.
 11. The air conditioner according to claim 8, wherein the ring-shaped stream-cutoff member has a diameter and a width, and the width protrudes from the inner surface of the casing in a substantially orthogonal direction and extends close to, without touching, the side end of the centrifugal fan.
 12. The air conditioner according to claim 8, wherein the ring-shaped stream-cutoff member is mounted on the inner surface of the casing and substantially fills a space defined by the inner surface of the casing and an interior surface of the bellmouth and the side end of the centrifugal fan.
 13. A centrifugal blower comprising: a casing having an air inlet, an air outlet, and a bell-mouth located near the air inlet; a centrifugal fan installed in the casing; and means for preventing an air stream from being swirled in a space between the inner surface of the casing and a side end of the centrifugal fan. 